Especially the base machine require the precision of transmission of the device to expect very much to it, and its control is more difficulty of heavy degree systematically in succession than arc casting, so resulted in the popularity and application of technology in succession of horizontal continous casting getting influence

尤其是拉坯機對其驅動裝置的傳動精度要求很高，其控制比弧形連鑄系統難度大，致使水平連鑄技術的推廣應用受到影響。

Self - directed innovation is not only difficult, but also investment effect period lasts long and it is extremely risky, devoting to independent development nearly determines the disadvantages in profits on short - term market

自主創新不僅工作難度大，而且投資見效期長，風險極大，從事自主開發，幾乎註定了在短期市場利益上的弱勢。

It is problem of education student analysis and the ability that solve a problem, make the student reachs level of hand of draw inferences about other cases from one instance, teach a student the various methods that solve a problem however, ask the student remembers these methods next, the result is, the student encounters the problem that has become to be able to be done, had not done " unripe problem " even if the problem with big difficulty also won ' t be done, sometimes, because the student did not understand truly, the problem that has become is complex also

According to features of diffcult anti - washing construction of pier foundation under compley hydroraphic, gological, and water potential conditions, combining construction condition methods, author analyze and conclude key points and difficulties of anti - washing construction of the fourth main pier of great sutong bridge, and difficulties in construction and relevant countermeasures